test: Fix race condition in machines.json migration test
test: Fix race condition in machines.json migration test

The migration of /var/lib/cockpit/machines.json is done by the
privileged bridge. However, in `testMachinesJsonVarMigration()` it is
not guaranteed that the privileged bridge gets started immediately, so
force that by using the /playground/test "superuser" button.

Move from the bogus IPs to the real IPs of the second/third test
machines, so that the machines actually become visible in the dashboard
instead of being hidden because of connection errors. This makes
screenshots less confusing.

Swap the check order to first wait for the machines to appear in the
dashboard, before testing the migration result. This makes debugging
tests slightly easier, as the migration won't start at all if for some
reason the machines don't get parsed from the JSON files in the first
place.

Fixes #7313 
Closes #7317 
Reviewed-by: Stef Walter <8a7fbf0f15d3ad982af54ef28f5c117d2494b76c@redhat.com>
michalskrivanek/cockpit,petervo/cockpit,andreasn/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,xhad/cockpit,deryni/cockpit,harishanand95/cockpit,cockpit-project/cockpit,xhad/cockpit,mareklibra/cockpit,mareklibra/cockpit,cockpit-project/cockpit,michalskrivanek/cockpit,cockpit-project/cockpit,martinpitt/cockpit,stefwalter/cockpit,mvollmer/cockpit,mareklibra/cockpit,larskarlitski/cockpit,cockpituous/cockpit,mareklibra/cockpit,petervo/cockpit,larskarlitski/cockpit,garrett/cockpit,michalskrivanek/cockpit,harishanand95/cockpit,harishanand95/cockpit,deryni/cockpit,larsu/cockpit,xhad/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,deryni/cockpit,larskarlitski/cockpit,mvollmer/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,garrett/cockpit,petervo/cockpit,andreasn/cockpit,cockpituous/cockpit,harishanand95/cockpit,cockpituous/cockpit,mareklibra/cockpit,harishanand95/cockpit,garrett/cockpit,cockpituous/cockpit,xhad/cockpit,andreasn/cockpit,larskarlitski/cockpit,stefwalter/cockpit,Scribery/cockpit,larsu/cockpit,garrett/cockpit,deryni/cockpit,larsu/cockpit,SotolitoLabs/cockpit,deryni/cockpit,martinpitt/cockpit,xhad/cockpit,larskarlitski/cockpit,deryni/cockpit,xhad/cockpit,andreasn/cockpit,Scribery/cockpit,Scribery/cockpit,petervo/cockpit,andreasn/cockpit,Scribery/cockpit,petervo/cockpit,stefwalter/cockpit,michalskrivanek/cockpit,larskarlitski/cockpit,andreasn/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,stefwalter/cockpit,michalskrivanek/cockpit,martinpitt/cockpit,SotolitoLabs/cockpit,cockpit-project/cockpit,SotolitoLabs/cockpit,michalskrivanek/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,stefwalter/cockpit,cockpituous/cockpit,petervo/cockpit,larsu/cockpit,Scribery/cockpit,moraleslazaro/cockpit,deryni/cockpit,xhad/cockpit,SotolitoLabs/cockpit,mareklibra/cockpit,garrett/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,harishanand95/cockpit,Scribery/cockpit,martinpitt/cockpit,mareklibra/cockpit,larsu/cockpit,andreasn/cockpit,larskarlitski/cockpit,petervo/cockpit,cockpit-project/cockpit,stefwalter/cockpit,larsu/cockpit,mvollmer/cockpit,michalskrivanek/cockpit,harishanand95/cockpit,Scribery/cockpit,moraleslazaro/cockpit,mvollmer/cockpit